The video appeared at the top of many users' feeds, but was
quickly removed.

The video appeared with Vine's warning prompting people to tap
the image to start playing. It's the same warning users see when
a video has been reported for displaying inappropriate content.

It is unclear how a video that was reported for having
inappropriate content became featured as an editor's pick. The
user name on the video was "nsfwvine" and had the caption,
"Dildoplay #nsfw #porn." Those are two common hashtags Vine users
tag pornographic videos as to make them easier to find. The video
showed a woman using a sex toy on a six-second loop.

UPDATE: Twitter has responded to the
incident and says the pornographic video was featured as an
Editor's Pick due to human error:

A human error resulted in a video with adult content becoming one
of the videos in Editor's Picks, and upon realizing this mistake
we removed the video immediately. We apologize to our users for
the error.